Arduino Charlieplexed Heart
The Arduino-controlled Charlieplexed LED heart uses a total of six wires to control 27 LEDs
Here is an Arduino-controlled Charliplexed LED heart. It uses a total of 6 wires to control 27 LEDs. Either PIC or AVR could easily be used for this project, but Arduinos are easy to program, very common, and have to have plenty of power left over for input.
For those not familiar, Charlieplexing is a technique for using N inputs to control N x N-1 LEDs. Check out www.instructables.com/id/Charlieplexing-LEDs--The-theory for a great explanation of this technique. Basically it allows you to drive a bunch of LEDs with very few pins.
1. Required materials
LEDs (27)—I would suggest red, but pink is cool, too ...